fix: coderabbit review

common/totp.go

@@ -113,10 +113,7 @@ func HashBackupCode(code string) (string, error) {
 
 // Get2FAIssuer 获取2FA发行者名称
 func Get2FAIssuer() string {
-	if issuer := SystemName; issuer != "" {
-		return issuer
-	}
-	return "NewAPI"
+	return SystemName
 }
 
 // getEnvOrDefault 获取环境变量或默认值